What is the first tube to be filled during blood specimen collection according to the CLSI order of draw?

The first tube to be filled during blood specimen collection according to the CLSI order of draw is the sterile tube for blood cultures. This is crucial because blood cultures are used to detect the presence of microorganisms in the blood, which can indicate infections such as sepsis. Collecting this specimen first helps to minimize the risk of contamination from other tubes or the collection equipment that may introduce extraneous microorganisms.

Using a sterile tube for blood cultures ensures that the sample accurately reflects the patient's bloodborne pathogen status. If any contamination were to occur from tubes filled subsequently, it could lead to false-positive results, impacting patient diagnosis and treatment.

This prioritization in the order of draw is intended to maintain the integrity of microbiological testing, as any contamination can significantly compromise the reliability of the results. The subsequent tubes are designed for other types of analysis, which are less sensitive to this risk of contamination.